IQ is roughly 50% genetic; school success is probably roughly 50% IQ (personal guesstimate). So my rough guess is about ONE-QUARTER of the DIFFERENCE in school success BETWEEN INDIVIDUALS is genetic. Hard work, and consistent work even more, make a big difference in practical success - in school or business. EDIT: I meant the differences between fairly normal levels of school success above - the difference between low achievers and the very best is probably more than 50% influenced by IQ
